That's a great idea! In the same vein, have you had a look at quickspec by Koen Claessen, Nicholas Smallbone and John Hughes? www.cse.chalmers.se/~nicsma/quickspec.pdf This reminds me of another idea, suggested by Jun inoue: look for functions by specification instead of examples. I will try your idea ASAP. As you say, I think that might be helpful for beginners, as you suggest, or even when you're not a beginner anymore but you start using a new library. Paul On Sun, Sep 19, 2010 at 07:41:21PM +0200, Roel van Dijk wrote:
Very interesting!
It got me thinking: if you combine this with the Arbitrary class [1] of QuickCheck you can use it check if you have defined a function that is "equal" to an already defined function.
Let's say I write the following function:
intMul ∷ Integer → Integer → Integer intMul x 0 = 0 intMul x n = x + intMul x (n - 1)
No you can automatically apply this function to a list of 100 generated inputs to get a list of input output pairs. Feed this into haltavista and it should tell you that you can replace your definition with Prelude (*). While such an observation is certainly not a proof it is still useful.
It would be a nice addition to a Haskell editor. Especially for those new to the language.
Regards, Roel
1 - http://hackage.haskell.org/packages/archive/QuickCheck/2.3/doc/html/Test-Qui...